Quick Summary– In this work we show that intense illumination actually changes the disorder and connectivity in a molecular aggregate, modulating exciton delocalization and superradiance. This shows that we can achieve chemical control over coherence in transition dipole moments.

Quick Summary-PbS NCs show both “trap” and band-edge emissive character at room temperature. Combining photon correlation Fourier spectroscopy with temperature dependent time resolved and static emission spectroscopy we build a model which demonstrates that these two states slowly interchange upon excitation over a kinetic barrier. This can help explain trends in QD emission energy, quantum yield, and linewidth as a function of size and temperature.

Quick Summary– Light harvesting nanotubes are self-assembled J-Aggregates which have extended delocalized excitons. We show that we can stabilize these aggregates to photodamage in a sugar based-matrix. This has enabled detailed cryogenic spectroscopy, including exciton-exciton annihilation. Surprisingly, we observe signatures of exciton exciton annihilation that indicate extremely long exciton migration. This exciton migration is mostly coherent, punctuated with transient localization by the environment.

Quick Summary- A neat method paper which that we can directly extract the biexciton emission dynamics from dilute solutions of chromophores, by resolving the lifetime of individual photons from two photon detection events. Code is available upon request.

Quick Summary- We developed a new all reflective two-dimensional spectrometer which uses angled mirrors to induce delays. This approach lets you use extremely broadband continuum generated pulses for multidimensional spectroscopy, while avoiding dispersion.

Quick Summary– In 2DES, electronic quantum coherence manifestes as oscillations at at the energy difference between states. We show that quantum coherence between the first two electronic excited state of CdSe QDs, indicating that quantum mechanical phase is maintained between electronic states for 100s of femtoseconds. In QD systems, a shared phonon bath correlates the phase of the carrier wavefunctions, maintaining coherence between states.

Quick Summary– The origin of long-lived observed coherent oscilliations in spectra of photosynthetic antenna proteins remains somewhat controversial. In this paper we apply a new signal processing tool, the linear prediction z-transform, to map coherent signals in 2D-spectra, according to decay rates, frequencies, and phase. We discuss how observation of long-lived coherences can be explained by invoking a correlated environment (bath).